C# 强制将空JSON数组转换为字典类型
问题是,PHP中的C# 强制将空JSON数组转换为字典类型,c#,json,json.net,C#,Json,Json.net,问题是,PHP中的json_encode()函数会给读取其输出的工具留下歧义。在PHP中,列表和字典都是相同类型的数组 echo json_encode([]); // [] echo json_encode(["5" => "something"]); // {"5": "something"} 在JSON.NET中,我想强制[]和{“5”:“something”}转换为字典类型。但是,它将[]识别为字典的禁止结构,并引发异常 我是否可以快速地将空JSON数组保留为null或强制它们转
json_encode()
函数会给读取其输出的工具留下歧义。在PHP中,列表和字典都是相同类型的数组
echo json_encode([]); // []
echo json_encode(["5" => "something"]); // {"5": "something"}
在JSON.NET中,我想强制[]
和{“5”:“something”}
转换为字典
类型。但是,它将[]
识别为字典的禁止结构,并引发异常
我是否可以快速地将空JSON数组保留为null或强制它们转换为空字典类型
最终解决方案
我修改了accepted answer,使其具有通用性,并可用于其他类型
public class DictionaryOrEmptyArrayConverter<T,F> : JsonConverter
{
public override bool CanWrite { get { return false; } }
public override bool CanConvert(Type objectType)
{
return objectType == typeof(Dictionary<T, F>);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
switch (reader.TokenType)
{
case JsonToken.StartArray:
reader.Read();
if (reader.TokenType == JsonToken.EndArray)
return new Dictionary<T, F>();
else
throw new JsonSerializationException("Non-empty JSON array does not make a valid Dictionary!");
case JsonToken.Null:
return null;
case JsonToken.StartObject:
var tw = new System.IO.StringWriter();
var writer = new JsonTextWriter(tw);
writer.WriteStartObject();
int initialDepth = reader.Depth;
while (reader.Read() && reader.Depth > initialDepth)
{
writer.WriteToken(reader);
}
writer.WriteEndObject();
writer.Flush();
return JsonConvert.DeserializeObject<Dictionary<T, F>>(tw.ToString());
default:
throw new JsonSerializationException("Unexpected token!");
}
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
您可以使用自定义的
JsonConverter
来实现这一点,尽管我认为这个解决方案还有一些不足之处:
private class DictionaryConverter : JsonConverter
{
public override bool CanWrite { get { return false; } }
public override bool CanConvert(Type objectType)
{
return objectType == typeof(Dictionary<string, string>);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.StartArray)
{
reader.Read();
if (reader.TokenType == JsonToken.EndArray)
return new Dictionary<string, string>();
else
throw new JsonSerializationException("Non-empty JSON array does not make a valid Dictionary!");
}
else if (reader.TokenType == JsonToken.Null)
{
return null;
}
else if (reader.TokenType == JsonToken.StartObject)
{
Dictionary<string, string> ret = new Dictionary<string, string>();
reader.Read();
while (reader.TokenType != JsonToken.EndObject)
{
if (reader.TokenType != JsonToken.PropertyName)
throw new JsonSerializationException("Unexpected token!");
string key = (string)reader.Value;
reader.Read();
if (reader.TokenType != JsonToken.String)
throw new JsonSerializationException("Unexpected token!");
string value = (string)reader.Value;
ret.Add(key, value);
reader.Read();
}
return ret;
}
else
{
throw new JsonSerializationException("Unexpected token!");
}
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
私有类字典转换程序:JsonConverter
{
公共重写bool可以写入{get{return false;}}
公共覆盖布尔CanConvert(类型objectType)
{
返回objectType==typeof(字典);
}
公共重写对象ReadJson(JsonReader阅读器,类型objectType,对象existingValue,JsonSerializer序列化程序)
{
if(reader.TokenType==JsonToken.StartArray)
{
reader.Read();
if(reader.TokenType==JsonToken.EndArray)
返回新字典();
其他的
抛出新的JsonSerializationException(“非空JSON数组不构成有效字典!”);
}
else if(reader.TokenType==JsonToken.Null)
{
返回null;
}
else if(reader.TokenType==JsonToken.StartObject)
{
字典ret=新字典();
reader.Read();
while(reader.TokenType!=JsonToken.EndObject)
{
if(reader.TokenType!=JsonToken.PropertyName)
抛出新的JsonSerializationException(“意外标记!”);
字符串键=(字符串)reader.Value;
reader.Read();
if(reader.TokenType!=JsonToken.String)
抛出新的JsonSerializationException(“意外标记!”);
字符串值=(字符串)reader.value;
ret.Add(键、值);
reader.Read();
}
返回ret;
}
其他的
{
抛出新的JsonSerializationException(“意外标记!”);
}
}
公共重写void WriteJson(JsonWriter编写器、对象值、JsonSerializer序列化器)
{
抛出新的NotImplementedException();
}
}
请在中查看此代码,或者您可以通过删除所有这些空数组属性来预处理json文本
//Will not work with formatted json due to whitespace
json = Regex.Replace(json, ",?\"[^\"]+\":[[]]", "");
private class DictionaryConverter : JsonConverter
{
public override bool CanWrite { get { return false; } }
public override bool CanConvert(Type objectType)
{
return objectType == typeof(Dictionary<string, string>);
}
public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
{
if (reader.TokenType == JsonToken.StartArray)
{
reader.Read();
if (reader.TokenType == JsonToken.EndArray)
return new Dictionary<string, string>();
else
throw new JsonSerializationException("Non-empty JSON array does not make a valid Dictionary!");
}
else if (reader.TokenType == JsonToken.Null)
{
return null;
}
else if (reader.TokenType == JsonToken.StartObject)
{
Dictionary<string, string> ret = new Dictionary<string, string>();
reader.Read();
while (reader.TokenType != JsonToken.EndObject)
{
if (reader.TokenType != JsonToken.PropertyName)
throw new JsonSerializationException("Unexpected token!");
string key = (string)reader.Value;
reader.Read();
if (reader.TokenType != JsonToken.String)
throw new JsonSerializationException("Unexpected token!");
string value = (string)reader.Value;
ret.Add(key, value);
reader.Read();
}
return ret;
}
else
{
throw new JsonSerializationException("Unexpected token!");
}
}
public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
{
throw new NotImplementedException();
}
}
//Will not work with formatted json due to whitespace
json = Regex.Replace(json, ",?\"[^\"]+\":[[]]", "");